Method of sizing cellulose fibers



Patented May 18, 1 926 J'UZDSON A. 1m cm, or" imw YORK, 1v. Y.-

mnrnon or srzrivo c LnULosE rrzenas Ho Drawing.

This inventionrelates-to a method of siz ing cellulose fibers by means of rosin size emulsions, during the process of paper manufacture.

The usual method of sizing paper pulp is to treat the fibers with rosin size and sulphate of alumina in the beating engine where they are mixed with the fibers and sizing precipitates formed in the pulp. Ei-' ther the size or the alum are added first. The pulp fibers are then discharges into a tank and pumped to a pointwhere they will flow through the Jordan engine and after that they may go direct toethe paper machine.

.It often happens that this method of operation does not properly size the paper, even though the size and alum are of good uality and the reason for this is the fact t at some fibers have a poor aflinity for rosin emulsions and when the size is added to the stock ahead of the alum, the rosin does not adhere unitormly to the surface of the fibers by. adsorption and when it is precipitated by the alum. it is in such a form that it drains from the fibers on the wire and is lost.

In order to change the character of such a cellulose so that it will adsorb the rosin from suspension or from colloidal solution, it is necessary to first treat the cellulose 'withsulphate of alumina and then later. add

the size emulsion so that it is precipitated on the fibers by the acidity within the fibers.

When this process is carried out in the beating engine however, this reaction does not take place because the beater mixes the size with the fibers so slowly that the size is coagulated by the'acid water surrounding the fibers and not by the acid fibers themselves so that no final improvement is obtained by using this method.

. alrea Application filed December 15, 1925. Serial 110 75325.

I have discovered, however, that the" size can be precipitated directly upon the-fibers if the mixing action is very rapid so that the size emulsions cover the fibers at the time that they are precipitated and I obtain this result-by the following method of op I first treat the fibers in the beating engine with the required amount of sulphate of alumina and allow them to remain in contact with the alum solution long enough for the fibers to adsorb a portion of the sulphate of alumina. The stock is then discharged from the beater andpumped to the J o-rdan .and as. the fibers pass. into the Jordan engine a continuous stream of sizing emulsioris passes into the Jordan along witli the 1 stock. i

In this machine the mixing action is' so rapid that the size .is uniformly spread over the fibers at the time of coagulation and, a, part of the coagulation is caused by the acidity already in the fibers. r

' In this way the pulp fibers are better sized than they would be if the sizing ingredients were all put into the beater where the mixing is slow and coagulation is rapid.

What I claim as my invention is 1. A method or sizlng paper pulp which. consists in .a continuous mixing treatment of rosin size emulsions and paper making fibers within the Jordan engme, the fibers dy having been made astringent by previous treatment with sulphate of alumina. 2. A method of sizingpaper-pulp; which consistsin treating the fibers while in the beater with sulphate of alumina-and adding 

